Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Hint: £210 / 7 = .....

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

no thay do not add to 210

should it be john get given 210 / 2 = 105

peter get given 210 / 5 = 42

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

210 / 7 =30

john get given 30 x 2 = 60

peter get given 30 x 5 = 150

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Yes you are correct.

*Last edited by SteveB (2013-11-01 08:23:14)*

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

£480 has to be split so that Jane gets £5 for every £3 that

is given to Paul.

Calculate how much Paul and Jane get.

Work out a total and check that it equals £480

*Last edited by SteveB (2013-11-01 08:19:47)*

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

can i do this one and some more and give you the answers to morrow night if ok with you?

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Okay see you tomorrow. Is 7pm okay ?

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

yes 7pm is fine with me see you then buy for now

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

The 2 extra questions are:

(Q1)

Joe is to get £9 for every £3 that Harry gets.

The total shared is £600.

Give the amounts that Joe and Harry are given.

(Q2)

Andrew is given £4 for every £7 that Ian is given.

The total shared is £88.

I shall call the most recent one in the thread question (3) it was:

(Q3)

£480 has to be split so that Jane gets £5 for every £3 that is given to Paul.

Calculate how much Paul and Jane get.

Work out a total and check that it equals £480

*Last edited by SteveB (2013-11-01 08:55:45)*

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Mandy: Did you manage them or are finding them difficult ?

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

hi steve b mandy here

(Q 1) is £600 / 12 = £50

joe get given 50 x 9 = £450

harry get given 50 x 3 = £150

(Q2) is £88 /11 = £8

andrew get given 8 x 4 =£32

ian get given 8 x 7 =£56

(Q3) is £480

480 / 8 =60

jan get give 60 x 8 =£480

paul get given 60 x 3 = £180

are these right or not

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

The answers to Q1 and Q2 look correct to me.

The answer to Q3 is nearly right in that the £180 figure is right, but the £480 is the original total,

so you have multiplied back by 8 when it should have been five.

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Do you want to try to get Jane's amount in Q3 correct ?

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

Q3 jan get given 60 x 5 = £300 am i right

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Yes well done. Now do you want to move on to something else like percentages?

Or do more ratio questions ?

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

i can not be on here long as we are off to see some firworks ok could you give me some more on ratio and also give me som on percentages please and i will do them for you and put them on here tomorrow night at around 7.00pm ok

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Okay I will send an email later this evening. Bye.

Copy of questions asked:

Percentages based on the last three quesions example no 1:

For question (1) the amounts of £450 and £150 out of a total

of £600 could be stated as a percentage.

Method:

450 / 600 = 0.75 (using a calculator)

This when multiplied by 100 gives 75.

So 450 is 75% of 600.

Similarly 150 / 600 = 0.25 or 25%

So 150 is 25% of 600.

Do the same for the numbers in (Q2) and (Q3) from yesterday.

What percentage is £32 of £88 ?

What percentage is £56 of £88 ?

What percentage is £300 of £480 ?

What percentage is £180 of £480 ?

*Last edited by SteveB (2013-11-02 09:42:38)*

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

bye for now hope to see you on here tomorrow night at around 7.00pm

Offline

**SteveB****Member**- Registered: 2013-03-07
- Posts: 574

Hi.....

(1)

Method:

450 / 600 = 0.75

150 / 600 = 0.25

This when multiplied by 100 gives 75 and 25 respectively.

Answer:

So 450 is 75% of 600.

So 150 is 25% of 600.

(2)

Method:

32 / 88 = 0.3636....

56 / 88 = 0.6363....

Answer:

So the percentages are 36% and 63% to the nearest whole number.

(3)

Method:

300 / 480 = 0.625

180 / 480 = 0.375

Answer:

So the percentages are 63% and 38% using the convention of rounding

upwards if there is a five after the digit being rounded even though

the number '0.5' is half way inbetween 0 and 1.

Comment:

Notice that they do not quite add up to 100%, but this is purely due

to the rounding, apart from that they would add up to 100% in problems

where you have worked out percentages of a total amount, and have included

all non overlapping components exactly once which add to form the total.

Notes on conventional rounding of numbers:

Let us suppose you are rounding to the nearest whole number a number

which has digits after the decimal point.

The following convention usually applies to numbers between 0 and 1:

0.1 rounds down to 0

0.2 rounds down to 0

0.3 rounds down to 0

0.4 rounds down to 0

0.5 is a borderline case we usually round this up to 1

0.6 rounds up to 1

0.7 rounds up to 1

0.8 rounds up to 1

0.9 rounds up to 1

Notice that 0.0 can sometimes be used to mean that the accuracy is to

one decimal place. Obviously to the nearest whole number it is 0, and

indeed it equals 0.

Similarly notice that 1.0 can be used to indicate that the accuacy is to

one decimal place. Obviously to the nearest whole number it is 1, and

it of course equals 1.

Often you will have to give an answer to a certain number of decimal places.

For instance:

Example 1: Round 1.476 to 2 decimal places.

Method: Since the second digit after the decimal point is 7 we look at the next

number. It is greater than 5. Therefore rounding up is appropriate.

Answer: 1.48

Example 2: Round 4.685 to 2 decimal places.

Method: Since the second digit after the decimal point is 8 we look to the next

digit. It is 5 and by convention an upward rounding occurs.

Answer: 4.69

Example 3: Round 3.595 to 2 decimal places.

Method: Since the second digit is a 9 care has to be taken because an upward

round of this number will cause an overflow carry since a "10" will result

meaning that the one higher place value digit to the left must go up by one.

As it happens the next digit to the right is 5 so upward rounding occurs by

convention. Therefore a 10 results and "59" becomes "60".

Answer: 3.60

A few for you to try:

Q1: Round to the nearest whole number 4.7

Q2: Round to the nearest whole number 7.5

Q3: Round to the nearest whole number 3.2

Q4: Round to 2 decimal places 8.469

Q5: Round to 2 decimal places 2.755

Q6: Round to 2 decimal places 3.933

Q7: Round to 2 decimal places 9.695

Q8: Round to 2 decimal places 1.005

Q9: Round to 2 decimal places 0.999

Q10: Round to 2 decimal places -4.867

Note that if you have something like 0.49999999... (recurring) then it is considered the same as 0.5 so

it rounds up to 1 not down to zero, so be careful about that exception. Most calculators will spot the

series of nines and round to 0.5 for you if that is the result of a division or similar so you do not usually

need to worry. Of course if you just had 0.49 and a finite series of nines then it rounds downward when

rounded to the nearest whole number. A number with many nines at the end that terminates is rare in practice,

but with calculators that do not automatically round you could get the recurring 9 happen by something like

the process that I have described here:

(This will not work on all calculators. Some will correct the rounding error automatically and others are caught out.)

A method to get 0.49999.... is to start with 0.4 in the calculator and then add (1/30) three times.

On my calculator it rounds up to 0.5 upon the third addition of 0.033333333.... but has retained a small

discrepancy. You can then subtract the 0.5 and then obtain "-1 E-14" in other words -0.00000000000001

a very small negative number: minus a hundred trillionth.

If you do 1 divide 6 then times 3 and subtract 0.5 then the answer is positive because the rounding at the

stage of 1 divided by 6 is an upward round - the recurring digit is 6, so it rounds up to 7. Since 7 times 3

is 21 the last digit is 1, which gives the positive extra 1 at the end of the 12 zeros after the five. Then subtract

the 0.5 and you get plus a hundred trillionth ("1 E-14") 0.00000000000001

The number of digits will vary according to what calculator is used.

Obviously the correct answer to 0.4 + (1/30) + (1/30) + (1/30) - 0.5 is exactly zero.

Also the answer to ((1/6) * 3) - 0.5 is also exactly zero.

The calculator answer is an example of an inevitable rounding error caused by the limits of accuracy,

some calculators will not be caught out by that trick depending on how they have been programmed to work.

*Last edited by SteveB (2013-11-18 08:52:01)*

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

Hi steveb & bob buddy happy new year to you both and Sorry I haven't been on here for some time but I have had some things to sort out and now I have done that ok? I would like to get back to doing maths ok hope you will help me out please? Can you send me an email from both of you to let me know what you think about this please? I am going spend 1 hour a day on maths is fun in the evening ok so can you send me a message back on here please like now?

Offline

Happy New Year, mandy!

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'You have made another human being happy. There is no greater accomplishment.' -bobbym

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

Hi agnishom mandy here happy new year to you I will be back on here from tomorrow night at around 7.00 pm ok hope you will be able to join us on here sometimes it would be good to hear from you again? Send me a message back please?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,597

Happy New Year!

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**mandy jane****Member**- Registered: 2010-09-23
- Posts: 1,126

Hi bobbym mandy here happy new year to you to? Hope you will join us sometime on herd from to morrow night from 7.00 pm. Send me a message back please?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,597

I will be here too but if the others are here I will not join in. I do not want to confuse you with many different opinions and methods.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline